smartypants

Hi All :

Just when I thought my 7 year battle with CEL issues was resolved, today I got another CEL 1491.

I cleaned the EGR port (I have a 99 so just one port), which was definitely blocked, as per the instructions in the DIY section and the Honda service bulletin. However, I did not drill out the plenum and insert the tube as it seemed frivolous to me.

The car ran fine for 3 days and then today it threw a 1491. Anyone else had this error reoccur after cleaning ? Is should I clean the EGR valve itself ? Does anyone have an engine pic with the exact location of the valve circled ?

Thanks for all those who reply !

smartypants

TLer trash

1491 code refers to the egr position sensor; I think it's insufficient lift detected. I'm pretty sure the lift sensor is part of the egr valve and not available separately.

fsttyms1

you may have a faulty EGR valve. (especially if you have had it plugged for 7 years and are just now doing something about it) Takeit off and try cleaning it.

smartypants

Thanks fsttyms1. Always helpful and a real resource for all of us.

Is the EGR valve the round piece under the oil fill cap with two bolts going into the intake manifold and a bunch of electrical and hose connections ?

Do you know which category the part is listed under ? I went through all the engine and fuel system diagrams and can't seem to find it.

Thanks in advance.

smartypants

hANDYcaptd

iTrader: (5)

#28. It was under Water Pump-Sensor

01tl4tl

sometimes you can remove the egr valve and shoot lube on its shaft to fix,

(Is ours vac operated like normal cars??) if so, apply hand operated vac pump and see if it opens and closes, thats all it does. Parts store will be able to test if you bring it it

there can be plugging at the opening right under the valve- very likely in your case

drilling out and the insert were part of the recall- you are correct, it doesnt help much and you know how to clean it every 75kmiles now

Seafoam 1 can to just under 1/2 tank of gas and see if that cleans up residual crud, egr port plugged backs up other systems
Try 1/3- 1/2 can in oil and drive 30 minutes then change oil while warm
You wont believe what it looks like inside the oil passages
1/2 can thru intake main vac port at TB- get pistons clean and injectors working- exhaust flowing,,it might run right again

smartypants

Thanks to everyone !

A new EGR valve is $150 ! Not cheap that's for sure !

smartypants

01tl4tl

you can use aftermarket valve if its really bad
I would try cleaning everything again first

sadate

can this be done with little to no disassembely?

ANC297

iTrader: (2)

Yes. Remove the plastic engine cover, and remove the barb from the vac line on the throttle body. Then just slide the hose off of the nipple. Attach a new hose into seafoam bottle, etc, etc.

01tl4tl

to be more specific- see the last few pages of the seafoam diy- there is a finger sized hose with a clamp you can squeeze open with your fingers- its the only hose like that anywhere near the master vac port at the connection of TB to manifold
- that will feed the entire manifold and spread the cleaner everywhere

its good to remove the hose between the air filter top and the TB inlet, spray clean the air plate inside- its gets grime from pcv system shot right at it- affects idle and throttle response

While its easy to reach, spray lube on the throttle return springs and assembly.

look at the diy pics and the car, read diy again and start

Or throw a full 16oz can in 1/2 tank of gas- that will do a decent job just not instantly

01tl4tl

do NOT use the can it comes in with a hose stuck in it- you want to keep the hose 1 inch above the fluid level or risk engine damage from too much at once- backwashing all over you~

a plastic water bottle will do for this job

or buy Deep Creep - seafoam aerosol version, way simpler to control and works on hundreds of other projects
If your big parts store doesnt carry it ck local places like Import parts specialty shops- they carry redline amz and both seafoams

smartypants

Hi All :

OK, so I removed the EGR valve earlier today and cleaned it as best I could. The valve has two ports, one round and one squarish. In the round port, there is a round brass part inside a steel collar. Using a pair of needle nose pliers, I gently pulled up on the brass portion and it came up about a quarter of an inch. This is clearly the valve portion of the part. While holding open the valve, I spayed carb cleaner down inside the assembly. The fluid came out of the square port, so I assume that is the return side of the valve. I sprayed some WD40 in there after the carb cleaner just to make sure it was well lubricated.

On the engine block side, the round and square ports are of course mirrored. I sprayed allot of carb cleaner down these ports but, I couldn't see very far into the block to verify if there was any further blockages.

If I continue to get 1491's I think I'm going to try and disassemble the ERG valve as it seems to easily come apart. After that, I think I just might live with the problem for good as I'm not going to spent $150 for some silly valve....maybe a trip to the junkers, who knows.

....and yes, pictures would have been a great idea !!

smartypants.

01tl4tl

so now the egr valve isnt sticking after lube treatment? good deal! go aftermarket it it quits working- no sweat

still need to remove manifold and clear the egr passageways for full effect~

smartypants

I won't know for a few days. That's how long it takes for the CEL to come on.

smartypants

smartypants

...an it goes on...

Well sports fans, I went over a bump today and both the CEL and the TCS lit up like a Christmas tree.

So now I'm totally confused. I've cleaned the EGR port, the EGR valve and tried to clean out the journals that connect the two parts and I'm still getting 1491's.

Anyone got any other bright ideas or than replacing the EGR valve ? Does anyone know were I could buy an aftermarket replacement valve ?

Thanks all.....

smartypants

smartypants

Hi All :

Update on the EGR valve cleaning and throwing a code the next day.

Since my last reset of the CEL and taking no further actions, I've had no new codes appear. I even checked to see if there was any pending codes and still nothing. I supect that since it has been years since the EGR valve has seen any exhaust gas, it needed a few days to "limber up".

I'm fully expecting to see this again, but will not take any further action until it decides to fail.

Thanks to all who replied. I'll update the thread when that happens.

smartypants

smartypants

Hi All :

So far, all is still well after a week and so I'm calling this one closed.

I think the learning in this case is to not react immediately if another code shows up right after the corrective action are taken. I'm thinking that maybe the computer "learns" to throw specific codes and needs to "unlearn" the habit. I know this sounds a little mystic but not knowing how the PCM manages the reported faults, I can only surmise that the one code I did get was false.

Hopefully the fix will continue to hold until the next time it clogs up. Thanks again to all who helped out.

smartypants.

01tl4tl

did you do a master reset of the system via the clock fuse or remove neg battery cable, or use a code scanner to clear the code?

smartypants

Hi 01tl4tl:

Yes, I have a scanner and reset the codes right after the cleaning.

01tl4tl

have you tried doing the master forced reset- by pulling fuse 13 on passsenger side- marked- clock
remove that fuse for a minute and reinstall
its the secret backup power to the ecu and is like unplugging a home computer- it makes it run a real self test diagnostic on startup

smartypants

In my pre-scanner days, I would disconnect the battery to clear the codes which is equivalent to pulling the fuse. It might do some resetting that clearing does not which could be useful. However, another ziner (who's name escapes me at the moment ) also had a a persistent code that came up once after some some fixing and never came up again.

Hopefully I have the same luck.

smartypants

01tl4tl

with all the trouble you have had...personally- if it were my car or I was the tech on it,,,
do a master reset and know its a real reset

the neg batt cable works the same as clock fuse BUT make sure you know the radio code before doing that~ thats why I suggest clock fuse- no effect on radio security

smartypants

So after three weeks of no codes, I now get at least one P1491 code a day. I am about to take it all apart again and shove a coat hanger down the journals to see if something is blocking the port way down inside the castings. I'm also going to remove the EGR valve again and see if I can pass the coat hanger through the base of the ERG valve out to the IM port.

If this doesn't work, I'm going to have to change the EGR valve next.

It might be helpful if someone could update the EGR DIY with a more detailed description of the cleaning process, like the coat hanger usage. I followed the Honda SB and it clearly needs much more detail. It might save someone (like me) from having the do the job twice ! If anyone has figured out a way to test if the cleaning is complete with the engine apart, I'd like to hear from them.

smartypants.

01tl4tl

spray carb cleaner- 3 cans, or if you have a solvent tank soak the intake manifold in it and rinse thru ports with the solvent wand and coat hanger as needed

With carb cleaner: spray and let soak- then spray and poke the hole(s) with a wire coat hanger--keep spraying and poking until the crud gets loose and goes out
that means as far as the wire will go- not just the opening to the port cleared
There will be more that it appears

Blow compressed air thru manifold to dry after water final rinse- blow compressed air from an air tank (good pressure, not gas station air gauge non-pressure) thru the egr port system and feel for air at the other end-
thats your test for done

mashimario

Hi all,

I have the same problem. The CEL came back again on after cleaning the EGR. I will try to clean it again.

Moreover, every time after driving the car for a while, the TCS light will be on.

I was wondering what cause the TCS light on? Is it related to the CEL?

big thanks to everyone!

MM

01tl4tl

the lights can mean 1000 things
If you live anywhere in the states (except Ca) you can get the codes read for free at parts stores
those will help us diagnose

did you remove the intake manifold from the engine and cleaned the egr port? - 1 on 99s, 6 on all later years- with carb cleaner and a wire hanger--thats what it takes

cel afterwards may be from loosened crud blowing thru exhaust got stuck on O2 sensor- just warm it up with 15 minute freeway cruise then drive it at 4000 rpm in 2nd gear for 5 minutes, that should clear itself
Or run some seafoam thru it to clean residue

mashimario

Hi 01tl4tl,

Sorry, I should input more information.
When the CEL came back, I read the code at autozone, which was P040 not same as the OP's. I am wondering if there will be a code for the TCS or not when it's on?

I think I will do the seafoam tonight.

Thanks a lot for your help.

-MM

smartypants

That's an interesting question. Why does the TCS light go on when an EGR error code is detected ? I always assumed the TCS was related to the ABS braking system and totally unrelated to the emissions system. How could one affect the other ?

01tl4tl

the warning lights get triggered by a number of things
Rarely do they relate to the exact problem- its just to get your attention to a real prob when all the dash lights come on

even the codes are not diagnosis- you have to piece the clues together to find the solution

mashimario

That really confused me coz every time after doing the reset, both of the lights CEL and TCS come back together.

mashimario

Should be P0401.

smartypants

Hi Sports Fans :

I just completed clearing the EGR port (again) using a coat hanger and shoving is down the ports with liberal amounts of carb cleaner. Unlike the first time, I did not see any obvious blockages. I also removed the EGR valve and shoved the coat hanger down that port as well. Unfortunately I do not have access to an air compressor to blow out the ports to make absolutely certain nothing is still nothing in there.

On a related note, I was able to remove the IM plenum without the throttle body. I simply undid the two bolts and two nuts and with all the plenum nuts and both removed, was able to lift the left side of the plenum enough for it to slide right off the TB. This meant I didn't have to remove all those connectors and vac hoses or touch the throttle cables. This approach cut the job in half !

I've reset the CEL and now we wait.......

smartypants

This is getting silly.....

After 4 days, the CEL came on........again ! I'm 99% sure it's a P1491 and in the next few days I'll hook up my reader to confirm.

So, my next plan is to change out the EGR valve as it couldn't be anything else......unless anyone has any other ideas ?


smartypants.